Optical apertures are used for sending optical signals to a target object such as a landscape in a range direction. Reflected optical signals from the target object may be received by the optical aperture and may be used to create images of the target object. While sending the optical signals, an optical aperture may be moved in a cross-range direction and reflected optical signals from the target object may be gathered by the optical aperture. Optical aperture synthesis is a technique for improving the cross-range resolution by movement of the optical aperture and combining the reflected optical signals to create a synthetic aperture. The synthetic aperture may provide increased cross-range resolution compared to a cross-range resolution provided by the optical aperture alone.
By receiving and combining the reflected optical signals from the range direction, while moving the aperture in the cross-range direction, two-dimensional images of range and cross-range can be created. Two-dimensional imaging can be extended to three-dimensional imaging by acquiring reflected signals in a third direction perpendicular to the range and cross-range directions. In view of the foregoing, creating resolutions in the third direction comparable to range and cross-range resolutions is desirable for three-dimensional imaging.